Abstract

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This study is aimed at evaluating the antimicrobial activity of ethanolic leaves extract of Terminalia catappa on some clinical bacterial isolates. The extracts were tested in vitro on Gram negative bacteria, it was obtained from ethanol using percolation method. The sensitivity of four clinical isolates of Escherichia coli, Proteus mirabilis, Morganella morganiis, Yersina enterocolitic was tested. The extract demonstrated strong in vitro antibacterial activity against these organisms at all concentration used (20μg/disc, 40μg/disc, 80μg/disc and 160μg/disc). Of these bacteria screened for antibacterial activity Morganella morganiis appeared to be the most sensitive organism exhibiting growth inhibition zone diameter of 15mm (160μg/disc), 14mm (80μg/disc), 12mm (40μg/disc), and 9mm (20μg/disc). While the least sensitive organism was observed on Escherichia coli 14mm (160μg/disc), 11mm (80μg/disc), 10mm (40μg/disc), 9mm (20μg/disc). Minimum Inhibitory concentration (MIC) of the extract was determined at 25ug/ml for the entire test organism. Although the extract revealed a strong inhibitory activity against the test organisms, growth was observed when test-tubes which showed absence of growth at MIC were sub-cultured on solid media to determine Minimum Bacterial Concentration (MBC) meaning that the extract was only Bacteriostatic at these concentration

Keywords: E. coli, Terminalia catappa, Morganella morganiis, Yersina enterocolitic, MBC, MIC.